Question

In natural convection, the denser portions of the fluid move downward because of the greater force of gravity, as compared with the force on the less dense.

(a) True

(b) False

I have been asked this question during an interview.

My question is taken from Engine Heat Transfer in chapter Heat Rejection and Cooling of IC Engine

Answer 1

The correct answer is:

(a) True

In natural convection, the denser portions of the fluid move downward because they are cooler and have a higher density, while the less dense (hotter) portions of the fluid rise. This movement occurs due to the force of gravity acting on the fluid, which causes the denser (cooler) fluid to sink and the less dense (warmer) fluid to rise, creating a natural circulation pattern.